Hearth is considered an average, small Selena world. It has a bumpy surface of small hills, mountains, craters, and canyons.
The moon is almost made entirely of rock and dirt. As such, very few precious metals are located within it. Small pockets of iron are sparsely placed across it. Very tiny pockets of cadmium are located there as well.
Originally, Hearth was the second major moon of Haven, second to the moon "Harmony". However after the aforementioned moon entered within the planet's roche limit, it was torn apart and became the vast "Rings of Harmony" ring system around planet Haven.
Now the moon exists as an Ecumenopolis, meaning the entire surface is covered within one large city. It has a very large population for an Ecumenopolis. In fact, it has the largest human populace of any Ecumenopolis in the Ambrosia Galaxy.
Hearth formed alongside its parent planet Haven, and its sister moon Harmony, in 4,500,000,000 BCE.
When it fist formed it had a wild retrograde orbit, opposite of its sister moon's standard prograde orbit. This lead to it to interacting with Harmony in a sort of gravitational tug of war as their opposite orbits would pull them closer to each other.
This would result in Hearth's favor as during the aforementioned gravitational tug of war, Harmony was gradually drifting closer to the planet Haven. This ultimately culminated with its entrance into the planet's roche limit in 3,777,020,105 BCE.
The first Ambrosian civilization to ever reach the moon was the Havenites when they launched a manned mission to the moon in the year 2,489,466,168 BCE. And with repeated trips to the moon throughout the 2,489,466,000 BCEs they would have a permanent, self-reliant colony established on the moon by the year of 2,489,466,150 BCE. More Havenite colonies would be established on the moon throughout four millennias until the moon would become a Ecumenopolis in 1,640,024,000 BCE.